Adding and Subtracting Fractions     Lesson 4-1 Adding and Subtracting Fractions with Like Denominators Lesson 4-2 Adding and Subtracting Fractions with Unlike Denominators Lesson 4-4 Estimating Sums and Differences of Fractions and Mixed Numbers Lesson 4-5 Adding Mixed Numbers Lesson 4-6 Subtracting Mixed Numbers Lesson 4-7 Choose a Computation Method